1. Field
Embodiments of the invention relate to oxides, and more particularly, to rare earth magneto-optical nanocrystalline oxides.
2. Description of the Related Technology
Magneto-optical materials can be useful in a variety of applications, including, for example, communications and optical systems, e.g., optical diodes. However, materials that possess both excellent magnetic proprieties and which are transparent to visible light can be very rare. For example, materials having useable magnetic properties can require the existence of free electrons, which can absorb light efficiently. Thus, relatively few materials have both high magnetic susceptibility and transparency to visible light.
Additionally, the production of rare earth oxides has been limited by processing technology. For example, single crystal oxide materials have been produced using melt processes, such as flux growth. However single crystal growth can be a relatively time consuming process. Furthermore, certain oxide compositions cannot be grown from a melt. Alternatively, oxide powders can be densified to produce optically transparent polycrystalline oxides. However, in practice polycrystalline oxides made using conventional densification processes have a high residual porosity, which can increase light scattering and can result in optically opaque oxides. Additionally, conventional ceramic processing methods, such as hot pressing, can require long processing times and high temperatures to produce porosity sufficient for optically transparent ceramics. High temperatures can lead to breakdown of nanocrystalline structures, and thus conventional ceramic processing methods can be unsuitable for making rare earth oxides.
There is a need for magneto-optic materials having a nanocrystalline structure, a high crystal density, a high magnetic susceptibility, and transparency to visible light. Furthermore, there is a need for magneto-optical device manufacturing processes having reduced processing times and improved temperature control.